Pumice: Description, Characteristics, and Other FAQs

In this article, you’ll obtain answers to common questions about pumice.

What Is Pumice?

Pumice is a volcanic rock that consists of highly vesicular rough textured volcanic glass. Vesicular means that it contains cavities or voids.

Most of the time, these cavities are filled with gas that escaped from lava during solidification.

Pumice is typically light colored.

Pumice stones are very porous and have low specific gravity because of all the tiny air bubbles distributed throughout the rock.

Pumice often forms during explosive eruptions when magma is ejected from a volcano at such a high velocity that it shatters into small fragments.

Where Can Pumice Be Found?

Pumice can be found all around the world.

It is most commonly associated with volcanic areas, such as Italy, Greece, Iceland, and the United States.

Pumice is also found in some non-volcanic areas that were once volcanically active, such as the Sinai Peninsula in Egypt and the Eifel region in Germany.

What is the Chemical Composition of Pumice?

Pumice is made up of silica and various other minerals, such as feldspar, pyroxene, and amphibole.

What Colors Can Pumice Be?

Pumice can be a variety of colors, including white, grey, yellow, pink, red, brown, and black.

The color of pumice depends on the chemical composition of the magma from which it formed.

For example, pumice that is rich in silica tends to be white or light colored, while pumice that is rich in iron and magnesium may be dark brown or black.

What Is The Moh’s Hardness Rating of Pumice?

Pumice has a Mohs hardness rating of 6.

This means that it can scratch any material with a Mohs hardness rating below 6, but it will be scratched by materials with a Mohs hardness rating above 6.

Other materials that have a Moh’s hardness rating of 6 include feldspar, apatite, and quartz.

Can Pumice Scratch Glass?

Pumice can scratch glass.

In fact, pumice is often used in industry as a gentle abrasive for polishing glass and removing minor imperfections.

What Are The Uses of Pumice?

Pumice is used in a variety of industries, including as an abrasive and horticultural additive.

Abrasive: Pumice can be used as an abrasive due to its rough texture. It is often used in polishes, pencil erasers, and exfoliants.

Horticultural Additive: Pumice can be added to potting soil to improve drainage and aeration. The small pores in pumice stones help to store moisture and nutrients, which can be beneficial for plants.

Stonewool: Stonewool is made by melting pumice and spinning it into fibers. It is commonly used as a horticultural growing medium and insulation material.

Other uses for pumice include in filters, scouring pads, and as a weight-loss aid.

Is Pumice a Rock or a Mineral?

Pumice is classified as a rock because it is composed of multiple minerals.

To be considered a mineral, a material must be composed of a single element or compound.

Pumice is typically made up of several minerals, including silica, aluminum, iron, magnesium, sodium, and potassium.

Is Pumice Igneous, Sedimentary, or Metamorphic?

Pumice is classified as an igneous rock.

Igneous rocks are those that form from the solidification of magma or lava.

In contrast, sedimentary rocks are those that form from the deposition of sediments, and metamorphic rocks are those that have been changed by heat or pressure.

What Is The Largest Pumice Stone Ever Found?

The largest pumice stone ever found was discovered in 2012 off the coast of Tonga.

The stone had a diameter of approximately 9.8 feet (3 meters) and weighed an estimated 19 tons.

What Is The Difference Between Pumice and Lava?

Pumice is a type of lava.

Lava is molten rock that has been ejected from a volcano.

Pumice is created when this lava cools and shatters into small pieces.

Is Pumice Foliated or Non-foliated?

Pumice is non-foliated.

Foliated rocks are those that have layers or bands of minerals, while non-foliated rocks do not have these layers.

Pumice is made up of small pieces of lava that have cooled and shattered, so it does not have the layers or bands that are characteristic of foliated rocks.

Is Pumice Felsic or Mafic?

Pumice is felsic.

Felsic rocks are those that are rich in silica and light-colored minerals, while mafic rocks are those that are rich in magnesium and iron.

Pumice is typically white or light-colored, due to its high silica content, so it is classified as a felsic rock.

Is Pumice Intrusive or Extrusive?

Pumice is extrusive.

Intrusive rocks are those that form from the solidification of magma below the surface, while extrusive rocks are those that form from the solidification of lava above the surface.

Pumice is made up of small pieces of lava that have cooled and shattered, so it formed from the solidification of lava above the surface.

Is Pumice Aphanitic or Phaneritic?

Pumice is aphanitic.

Aphanitic rocks are those that have small or no crystals, while phaneritic rocks are those that have large crystals.

Pumice is made up of small pieces of lava that have cooled and shattered, so it has no large crystals.

Is Pumice Volcanic or Plutonic?

Pumice is volcanic.

Volcanic rocks are those that form from the solidification of lava, while plutonic rocks are those that form from the solidification of magma.

Pumice is made up of small pieces of lava that have cooled and shattered, so it is classified as a volcanic rock.

Is Pumice Valuable?

Pumice is not considered to be valuable in terms of monetary worth.

However, it does have a number of practical uses, as described above.

Is Pumice Rare?

Pumice is not considered to be rare.

It is found in many volcanic areas around the world.